Organosilane quaternary nitrogen compounds have been employed effectively for imparting water, soil and stain repellency and reducing and/or eliminating microbial contamination when applied to a variety of surfaces. For instance, bacterial, viral and fungal contamination may be reduced or eliminated when such organosilane quaternary compounds are applied to surfaces. Commercially available quaternary ammonium organosilanes which have been used for this purpose include 3-(trimethoxysilyl)propyidimethyloctadecyl ammonium chloride, 3-(trimethoxysilyl)propyldidecylmethyl ammonium chloride, and 3-(trimethoxysilyl)propyltetradecyidimethyl ammonium chloride. The following patents and patent applications disclose the use of siliconized and/or non-siliconized quaternaries, solvents and surfactants/detergents for the cleaning and/or water repellent treatment of substrates: U.S. Pat. Nos. 4,005,028; 4,005,030; 6,559,111; 6,897,191; 6,809,072; U.S. Publ. No. 2005/0089695; U.S. Publ. No. 2005/0020474; U.S. Publ. No. 2003/0109395; U.S. Pat. No. 6,881,247; U.S. Publ. No. 2003/0091641 and U.S. Pat. No. 5,426,204.
Many different types of hard and soft surfaces have also been cleaned of soluble soil, provided with a water and soil repellent finish and rendered antimicrobial by coating with different agents. For example, U.S. Pat. No. 6,994,890, which issued on Feb. 7, 2006 (Ohlhausen and Ludwig), discloses a “Cleaning and Multifunctional Coating Composition Containing An Organosilane Quaternary Compound and Methods of Using” from aqueous systems with hydrogen peroxide. Such compositions are exceptionally effective in removing water and oil soluble soil from surfaces while simultaneously providing a water and soil repellent barrier coating for easier cleaning and to reduce microbial contamination.
Further improvements in surfactant-free storage-stable liquid cleansing and multifunctional coating compositions to satisfactorily or completely remove insoluble buildup have been made with reference to U.S. application Ser. No. 11/175,583, filed Jul. 6, 2005, entitled, “A Surfactant-Free Cleansing and Multifunctional Liquid Coating Composition Containing Nonreactive Abrasive Solid Particles and An Organosilane Quaternary Compound and Methods of Using (Ohlhausen and Ludwig). Because of the reactivity of the organosilane quat, it is employed with nonreactive abrasive solid particles to cleanse insoluble surface soil and simultaneously impart a water, soil and stain repellant barrier coating.
Thus, organosilane quats are among the world's most flexible, thin-film surface modifying compounds. They are substantive to hard and soft substrates alike. They yield invisible, but durable, water, soil and stain repellent barrier coatings when applied to siliceous, plastic, metal, skin, and textile surfaces from water-based compositions.
However, the chemical nature and structure of quats are such that they are highly reactive, but not storage-stable. They are inherently subject to condensation and cross-linking until they are extensively diluted and/or compounded with compatible additives. Also, organosilane quats are typically offered by their manufacturers in concentrations of 40-72% in methanol and other solvents, which are flammable, toxic and poisonous. Moreover, as such concentrated quats age, their viscosities, appearance, color and compounding ability vary significantly.
For all of the far-reaching performance benefits of organosilane quats, their relative lack of storage stability, handling and shipping hazards, until extensively diluted to make them economically viable, have limited their formulation and sales prospects. Thus, there is a clear need for storage-stable, non-flammable forms of organosilane quats. There is a particular need for them in concentrations that can be readily formulated by manufacturers and end-users alike into a variety of surface care products where the residual water, soil and stain repellent characteristics of the organosilane quats offer desirable properties and benefits. Examples of such products range from windscreen washer fluids and glass cleaners to multifunctional cleaners and antimicrobial barrier coatings.